As the title says, why diesel engines produce less CO2 than gasoline engines and how is this related to the more torque and less power in diesel engines? PLEASE only a fluid dynamics or thermodynamics approach. Spent hours on searching to find why petrol engines produce more CO2 emissions (or vise versa) but nothing on the web. I understand the standard explanations on longer stroke, more RPM, higher compression ratio but I am not looking on this kind of stuff. I am looking for a thermodynamic approach with efficiencies, mass flow rate etc. Any kind of help will be appreciated.